JRuby, RVM and Vim walk into a (performance) bar

22nd June 2017

I'm not sure why RVM is still my default Ruby version manager yet the issue at hand should be reproducible on rbenv too.

Let's add a bit of context to this: we have an API written in Ruby and running on JRuby i.e. via JVM which implies slow start-up times compared to CRuby (yes, even with export JRUBY_OPTS='--dev'). I use Vim 8.0.502 which of course comes by default bundled with Tim Pope's vim-ruby .

The problem: since I've switched to JRuby I started to notice a slowdown whilst working in Vim with .rb files. I did not pay too much attention to it at first (read almost for a month) but today it really started to bug me. I had no idea what was causing the slowdown so I tried Vim's trusty command-line option: